Shaft-coupling for speedometers.



i G. D. PEEBLES.

SHAFT COUPLING FOR SPBEDOMETERS. APPLIQATI N FILED 00122, 1213.

1, 1 1 1,670. Patented Sept. 22, 1914.

UNITED STATES OFFICE.

scenes 1). PEEBLES, or neurosis, mssacnussr'rs, assrcno'a T0 STANDARDTHER- moms'rsa COMPANY,- or' BOSTON, mnssacnusnrrs, A convenience: ormeme.

SHAFT-COUPLING F012. srnnnomnrnns.

Specification of Letters Patent. Patented Sept, 22, 1914,

Application filed October 22, 1913. Serial No. 796,717.

To all whom it may concern Be it known that I, GEORGE D. PEEBLES,citizen of the United States, residing at Medfo'rd, county ofMiddles'ex, State of Massa- 'chusetts, have invented a certain new anduseful Improvement in Shaft-Couplings for Speedometers, of which'thefollowlng s a specification, referencebeing had therein to theaccompanying drawings.

Speedometers are usually connec'tedby a coupling with a flexible shaftwhich inturn is connected with'the' driving mechanism of the vehicle.The driving connection between the flexible shaft and the speedometersome times employed is to provide the end of the flexible couplingwith atongue and to 1'0- vide the endo-f the main spindle or she. of thespeedometer with a slot with which the said tongue on the driving shaftshould en ga e when the two members are coupled together, so that thedriving shaft may rotate the speedometer main spindle, the couplin endof the. flexible shaft being connected with a tubular couplin having aunion formed with an internal t read which screws onto an externallythreaded hollow stem at the base of the speedometer case within which iscontained the speedometer shaft or main spindle. When the coupling isscrewed up onto the stem of the speedometer case it should bring thetongue of the flexible shaft into engagement with-the slot in thespeedometer main spindle. It frequently happens that when the couplinghas been I. a i

'the ordinary construction the flexible driving shaft isnonslidable'backward on account of the manner in which it is seated inthe coupling, and the speedometer main spindle has its other endconnected with the rack spindle which engages the'odometer plate. Theresult is that the odometer plate usually bends or buckles under thestrong pressure occasioned by screwing up the coupling sleeve. As theodometer plate serves as the bed on which are mounted the variousmechanisms of the speedometer, if the odometer plate is bent or buckledthat will disarrange the delicate parts of the speedometer, especiallythe various gears and dogs by which the recordin number wheels are 1actuated. Now after t ecoupling has thus been screwed up far enough sothat it bends the odometer plate in the manner described, 1f the drivingmechanism is started in motion, as soon as the flexible shaft hasrotated far enough to turn the tongue through a sufiicient portion of arotation to bring it into alinement. with the slot in the speed:

ometer main spindle the pressure may then besufiicient to cause the,tongue to engage w1t h the slot and rotate the speedometer main and rackspindles. If so, it will move or attempt to move the various rotaryparts of the speedometer and on acount of their disarranged position itresults in great damage to the mechanism.

The object of the present invention is to provide in the couplin ayielding seat for the flexible drivin sha t so that in the event of thecross coupling as above described the continued rotation of the couplingwill cause the flexible driving shaft to yield longitudinally, therebyrelieving the pressure on the speedometer spindle and preventing thebending or buckling of the odometer plate. Then after the drivingmechanism is started and the flexible shaft is rotated a sufficientportion of a rotation to bring the tongue into alinement with the groovein the end of the speedometer main spindle the tension of the yieldingseat of the flexible shaft will cause the tongue to snap into engagementwith the slot so that the speedometer will operate in the usual andproper manner.

The invention will be fully understood from the following descriptiontaken in connection with the accompanying drawings, and the novelfeatures thereof will be point ed out and clearly defined in the claimsat the close of the specification.

In the drawings-Figure 1 is a longitudinal section of a speedometer, aportion of the flexible shaft and a coupling embodying the invention,showing the parts in the position where thetongue is properly engaged inthe slot and properly coupled. Fig. 2 is a longitudinal section on line2-2 of Fig. 1. Fig.

3 is an enlarged longitudinal section showing the parts in cross coupledposition. Fig. 4 1s a cross sectional view on line 44 of Fig. 3.

Referring now to the drawings,-1 represents the speedometer case havinga bevel glass cover 2 on its outer end held in place by the spun bezel3. It is formed with an interior annular shoulder 4 on which is seatedthe odometer plate 5 which serves as a mount for the various shafts andbearings for most of the mechanism of the speedometer. It is deemedunnecessary to describe this mechanism in detail, but briefly some ofthe parts are as follows: 6 is the tenths wheel carried by the shaft 7on which is mounted a ratchet wheel 8 which is engaged by the pawl 10,said pawl 10 being actuated by an eccentric 11 mounted on a shaft 12which carries a pinion 13, said pinion 13 engaging with a worm 14 on ashaft 15. Said shaft 15 carries a pinion 16 which engages with a worm 17mounted on the speedometer rack spindle 18. 19 represents the annularinternal gear trip ring. The number wheels 20, 21, 22, 23 respectivelyare mounted on the shafts or studs 24, 25, 26, 27 and are formed withhubs carrying thereon, respectively the star wheels 28, 29, 30 and 31respectively. The hubs of the number wheels 20, 21, 22 are providedrespectively with driving dogs 32, 33, 34 which respectively are adaptedto engage with the star wheel on the hub of the next higher number wheelin the usual manner.

Projecting down from the under side of the odometer plate centrallytherewith is a pin 35 which serves as a centering pin for the aperturedupper end of the speedometer rack spindle 18 which bears against theunder side of the odometer plate. The worm 17 already referred to ismounted fast upon the upper portion of the rack spindle 18. The rackspindle as shown passes through the cylindrical rack 36 which is engagedby the segment gears 37, 38 which form a part of the governor but whichform no part of the present invention. The lower end of therack spindle18 is slotted and engages a pin 39 on the upper end of the shaft 40whose lower end is forked or formed with a slot 41. The flexible shaft42 terminates in a link 43 having a tongue 44 on its end which forconvenience is hereinafter referred to as the coupling end of thedriving shaft and which is adapted to engage with the slot 41 in thespeedometer main spindle when the tongue and slot are brought intoalinement with each other so that when the shaft 42 is rotated it willrotate the main spindle 40 and thereby also rotate the rack spindle 18'connected therewith. The link 43 is formed with an annular groove 45,surrounding which is a collar 46 which is held in engagement with thesaid link by the ball bearings 47 which are seated partly in the groove45 of the link 43 and partly in the annular internal groove in thecollar 46 so that the flexible shaft can freely turn within said collar.Said collar 46 "will be referred to hereinafter as the head of theflexible shaft. The collar 46 is first formed with the sides extendingup without any inturned flange at the top.- It is assembled with theflexible shaft 43 in that form, and the balls 47 canbe easily insertedinto the cup formed by the collar and the annular groove 45 of theshaft. After the parts are then assembled, the top of the collar'is spunor pressed in, forming the inturned upper flange 52 as shown in Figs. 1and 3, which securely retains the balls in position. A sleeve 48 isprovided into which the flexible shaft extends, and a coupling hat orunion 481 has a swivel connection with said sleeve 48 so that the union481 can rotate without rotating the sleeve 48. The upper'end of saidunion or nut 481 is internally screw,

threaded so that it may be screwed onto the externally threaded stem 49of the speedometer case 1 through which the speedometer, main spindle 40extends. The said sleeve 48 is formed with an annular internal shoulder50 on which is seated a coil spring 51. The lower end of the collar 46is seated upon said spring 51 which thereby forms a sure allowing theflexible shaft to be pushed backward, compressing the spring, and whenthe backward pressure is relaxed the said spring will tend to resume itsnormal form and carry forward the head or coupling end of the flexibleshaft again.

Now in the operation of the device,'when the flexible shaft is to becoupled up with the speedometer, the union 481 will be screwed onto thethreaded stem 49 of the speedometer case and if after being set part wayup the tongue 44 strikes crosswise of the slot 41, so that the tonguecannot enter the slot, the continued screwing up of the union while theends of the two shafts are in contact with each other will cause a backpressure of the collar 46 on the spring seat 51, compressing the spring51 more and more as the coupling is set up so that the driving orflexible shaft 42 will yield backward as fast as the coupling is set up,and thereby take up the pressure in a large degree so that the mainspindle 40 and rack spindle 1.8 will not have to yield and there will beno buckling or bending of the odometer plate 5. Now when the drivingmechanism mum tongue 44 to snap into the slot 41 and make I will beginto rotate with the shaft 42 and a as.

actuate the recording or indicating mechanlsm.

Itis' obvious that "the form of the coupiin and union shown may beemployed in com inationwith any two shafts having a tongue and slotconnection such as that shown in connection with shafts 40 and 43, oneofthe shafts being formed with a head 46. In other 'words the form ofshaft and coupling described is not necessarily limited to use with aspeedometer. The shaft 40 might be connected with otheffiichanism',

there being a proper case around'the shaft 40 with which the union 481maybe connected. v

What I claim is:

1. A. speedometer driving shaft having head, in combination with acoupling consisting of a sleeve having a shoulder on the inner peripheryintermediate the ends, a union connected with said sleeve having aninternally screw threaded portion between the said shoulder and one endfor connection with the speedometer case, and a coil spring seated onsaid shoulder on the side toward the said threaded portion of the unionto form a seat for the said head of the driving shaft while .the saidshaft extends back through the opposite end of said coupling:

2. A speedometer driving shaft having a head, in combination with acoupling consisting of a sleeve having an annular shoulder on the innerperiphery intermediate the ends, a union connected with said sleeve andhaving an internally screw threaded portion between the said shoulderand one end for connection with a speedometer case, and a coilspringseated on said shoulder on the side toward the said threaded portion ofthe union to form a seat for the said head of the driving shaft, thesaid annular shoulder forming a restricted aperture for passage of saiddriving shaft, the interior diameter of said sleeve at the union endbeing sufficient to receive the head of the shaft.

3. A speedometer having a shaft or .the coupling end of the said shaft,in combination with a coupling sleeve having a shoulder on the innerperiphery thereof in termediate the ends, a union connected with said's'leete aiid having an internally screw threaded portiou'for connectionwith the screw threiided stem of the speedometer case, and a coil springseated on saidshoulder on the 'side toward the saidthreaded portion ofthe union to form a seat for the said collar of the driving shaft, saiddriving shaft extending back through the rear end of said sleeve. '1 I4. A speedometer having an actuating shaft or spindle, a driving shaft,one of said; two shafts being formed with a tongue on" the end thereofand the other of: said two shafts being formed with a slot whereby saidtwo shafts-are adapted to engage with eachother, in combination with ascrew threaded union a coupling comprising a sleeve having at one'end aswivel connection' with said screw threaded union, a speedometer casehaving an apertured portion surrounding the speedometershaft andthreaded to receive the threaded end of said union said driving shaftpassing through said sleeve andbeing provided with a collar adjacent theportion which engages the speedometer shaft, and a spring seat withinsaid coupling sleeve on which the said collar is seated whereby the saiddriving shaft is permitted to yield backward under longitudinalpressure.

5. A speedometer having a shaft .or spindle connected with the drivingmechanism of the speedometer and a case having a threaded tubular stemsurrounding the said shaft, a driving shaft connected with the drivingmechanism of the vehicle or machine with which the speedometer is to beconnected, one of said two shafts having at one end thereof a slot andthe adjacent end of the other of said shafts having a tongue which isadapted to engage with said slot whereby the rotation of the drivingshaft will rotate the speedometer shaft, a coupling sleeve having at oneend a tapped out union adapted to engage with the threaded stem of thespeedometer case, said sleeve also being formed with a spring seat andsaid driving shaft being formed with a shoulder which is adapted to beseated on said spring while the end of the shaft is inclosed within saidsleeve, said spring seat yielding to the pressure of the tongue on theend of one shaft againstthe end of the other shaft if the said tongue iscrosswise of the slot when the coupling is screwed up.

6. A speedometer having a shaft or spindle connected with the actuatingmechanism of the speedometer, a driving shaft, one of said two shaftsbeing formed with a tongue at one end and the other of said two shaftsbeing formed with a slot at oneend whereby the two shafts may be engagedtogether so that the rotation of the driving shaft will rotate thespeedometer shaft, a' casing for the speedometer, a coupling sleevewhich surrounds the connecting end of said driving shaft and having aspring seat on which is seated a flanged projection on the drivingshaft, said couplmg being formed with'a screw threaded union portion andsaid casing being formed with a threaded with which said union end ofthe s eeve is adapted to be engaged to draw the adjacent ends of the twoshafts together.

7. In combination with a speedometer, a speedometer shaft, a speedometercase formed with an apertured portion surrounding the speedometer shaft,a screw threaded union which engages with said apertured portion of thespeedometer case, a driving shaft having a head, and a couplingconnectedvwith said union and having a spring seat for the head of thedriving shaft which yields in a backward direction to pressure on theend of the shaft.

8. In combination with a speedometer, a .speedometer shaft, a caseformed with an aperture through which the speedometer shaft passes, adriving shaft having a laterally extending swivel head thereon, atubular coupling through the rear end of which said driving shaftpasses, said coupling being provided with a yielding seat for the headof said driving shaft, and a tubular union, one end of which isconnected with saidcoupling and the other end of which is secured tosaid casing at the said apertured portion thereof.

, 9. In combination with a speedometer, a speedometer shaft, a caseformed with an aperture through which the speedometer shaft passes, acoupling, a tubular union for connecting said coupling with the saidapertured portion of the speedometer case, a driving shaft which passesthrough the rear end of said coupling and has a flanged head, and anapertured spring seat within said coupling, the rear face of saidflanged head of said driving shaft being seated upon said spring seat.

10. In combination, two shafts one of said two shafts being formed witha tongue at one end and the other of said two shafts being formed with aslot at one end, whereortion by the two shafts maybe engaged together.-

ond shaft passes, and a tubular screw.

threaded union which engages with the apertured portion of a casing forthe second shaft and is connected with the said coupling. I I

11. In combination, two shafts, a casing for one of said shafts formedwith an aperture through which the said first shaft passes, a screwthreaded union which en gages with said apertured portion of saidcase,said second shaft having a head, a coupling connected with saidunion and having a spring seat for the head of said second shaft whichyields in a backward direction to pressure on the end of said shaft.

12. In combination with a speedometer, a speedometer shaft, a caseformed with an apertured portion through which the speedometer shaftpasses, a driving shaft, one of said two shafts being formed with a slotand the other of said two shafts being formed with a tongue adapted toengage with the slot of the other shaft, said driving shaft being formedwith a flange head, a tubular coupling surrounding said head, saiddriving shaft passing out through the rear end of said coupling, aspring seat within said coupling for the head of said driving shaftvwhich yields in a backward direction to pressure on the end of theshaft, and a tubular union, one end of which engages with said couplingand the other end of which engages with the apertured portion of saidcase.

' In testimony whereof I aflix my signature, in presence of twowitnesses.

GEORGE D. PEEBLES. Witnesses:

WILLIAM A. COPELAND, Anon H. Momuson.

